Two-part hair dye compositions or two-part hair bleach compositions which include a first agent containing an alkaline agent and a second agent containing hydrogen peroxide are widely used. Generally, such a two-part hair dye or bleach composition is an agent in the form of a gel or cream which has a post-mixing viscosity of about several thousand to several tens of thousand mPa's so that after applying on the hair the agent does not trickle down while being left.
To carry out hair dyeing or bleaching without any unevenness using a gel- or cream-formed two-part hair dye or bleach composition, first the first and second agents have to be vigorously shaken or mixed in a mixing container in order to carefully mix them. Furthermore, to carry out hair dyeing or bleaching without any unevenness using a gel- or cream-formed two-part hair dye or bleach composition, since the mixed solution has a high viscosity as mentioned above, not only skill is required, but the hair must be “pre-blocked” (in other words, the hair must be braided into sections at the front, sides, and rear of the head). Thus, required are a lot of time and effort to carry out such dyeing or bleaching.
On the other hand, two-part dye or bleach compositions are known which contain a surfactant in at least one of the first or second agents as a foaming agent so that the mixed solution of the first and second agents is discharged in a foam from a foamer container (Patent Documents 1 and 2). According to this two-part dye or bleach composition, by discharging the mixed solution of the first and second agents in a foam, the mixed solution can be simply applied on the hair without any unevenness. This allows a finish without any unevenness to be more easily obtained compared with when coating a gel- or cream-formed two-part hair dye or bleach composition.
Patent Document 1: JP-A-2004-339216
Patent Document 2: JP-A-2006-124279